As stated by the source, the Health Care Satellite Account presents two versions of the accounts. One version uses data from the Medical Expenditure Panel Survey (MEPS) - referred to as the "MEPS Account" - which is the only nationally representative survey that contains detailed expenditure information by disease. Due to the relatively small sample size the MEPS Account produces more volatile estimates across years. To address this issue, BEA presents a second version of the satellite account - referred to as the "Blended Account" - which blends together data from multiple sources, including large claims databases that cover millions of enrollees and billions of claims. The key difference is that the MEPS Account and Blended Account use different methodologies and data sources to allocate expenditures across different diseases within the medical services by disease category.